It _mostly_ has, but there was a brief time in history where in regard to SCOTUS they actually cared only that the person being considered could do the job. There was still an attitude of this when I was a child and learning about it in school, and several of my teachers mentioned it. I'm pretty sure that we can never go back to that as long as social media is an influence. If you use social media a bunch you're basically just being lead on the trail of breadcrumbs to become a zealot for one side or another on every issue. Politicians and anyone else _are not_ immune to this, and it takes some reserve to not be tangled up into it. The algorithms they use to fill your feeds are so good these days that they will just keep serving you shock posts as soon as you start clicking them. Eventually, you won't even see 'the other side' viewpoint as just go down the rabbit hole for whatever is closer to your fundamental beliefs. Most people are effectively herded into a reality tunnel in that way. My FB will look nothing like yours and that'll be the same for anyone who diverges from another person views. We literally don't see the same news or sensational posts. That's the 'game'...
Honestly, it started with the reaction to Obama, which slightly predated the widespread adoption of social media.
I vividly remember, before and soon after he was elected, the racist, hateful chain emails in my AOL (yes, AOL) inbox that my Republican friends and family would forward to me.
I still very vividly remember how John McCain was appalled when a woman stood up at his rally and said she can't trust Obama, "he's an Arab". The Tea Party continued to gain strength and seemed to blindside the conventional Republican Party, until it found a champion in Donald Trump and morphed into Trumpism.
Fundamentally ... put aside the accusations of socialism, put aside all the things Republicans don't like about a Democrat ... fundamentally, I have never been able to understand the absolute horror the Tea Party felt about President Obama, who was a moderate Democrat who killed Bin Laden. Books like "Obamanation" and "The Great Destroyer" were eaten up. Fox News, America's most watched primetime news network, had Hannity & Colmes .. then it became just Hannity ... Bill O'Reilly, Glenn Beck, Jeanine Pirro, Tucker Carlson ... they became more and more fringe, or were ousted by scandal, or ousted for not becoming extreme enough and loyal enough for Donald Trump. I remember vividly Sean Hannity repeating his full name, "Barack Hussein Obama", emphasizing the "Hussein" part, and asking innocently, "What's wrong with using his full name?"
It was this extreme hatred of Barack Obama in search of a reason to justify it, that caused McConnel to say their #1 goal was to prevent Obama from being re-elected (rather than their #1 goal being to govern). It was that same perception of Obama as "other" that made them resist letting him appoint a Supreme Court Justice.
So where am I going with all this? I truly believe that without racism, the Republican Party's recalcitrance against Barack Obama - which has evolved into Trumpism today - cannot be explained. Right after our first black president was elected - even though he was a moderate - Republicans embrace Donald Trump, a man who championed the worst racist lies against Obama and whose agenda fits no pattern other than opposes literally everything Obama pushed for. And that underlying racism has added a lot of fuel to the partisan fire, resulting in battles like we see today over Supreme Court Justices. I truly believe this. Social media feeds into it but I believe it fills a need, a need caused by racism, in part, to begin with. A person feels a strong opposition to black and brown people - and others too. Why does one feel that way? How can one justify that feeling and put it into action? Right wing social media provide answers.